GLOBAL WATER PATHOGEN PROJECT PART THREE. SPECIFIC EXCRETED PATHOGENS: ENVIRONMENTAL AND EPIDEMIOLOGY ASPECTS PARAGONIMUS SPP. Jong-Yil Chai Seoul National University College of Medicine Institute of Parasitic Diseases Korea Association of Health Promotion Seoul, South Korea Bong-Kwang Jung Institute of Parasitic Diseases Korea Association of Health Promotion Seoul, South Korea Copyright: This publication is available in Open Access under the Attribution-ShareAlike 3.0 IGO (CC-BY-SA 3.0 IGO) license (http://creativecommons.org/licenses/by-sa/3.0/igo). By using the content of this publication, the users accept to be bound by the terms of use of the UNESCO Open Access Repository (http://www.unesco.org/openaccess/terms-use-ccbysa-en). Disclaimer: The designations employed and the presentation of material throughout this publication do not imply the expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The ideas and opinions expressed in this publication are those of the authors; they are not necessarily those of UNESCO and do not commit the Organization. Citation: Chai, J.Y. and Jung, B.K. 2018. Paragonimus spp. In: J.B. Rose and B. Jiménez-Cisneros, (eds) Global Water Pathogen Project. http://www.waterpathogens.org (Robertson, L (eds) Part 4 Helminths) http://www.waterpathogens.org/book/paragonimus Michigan State University, E. Lansing, MI, UNESCO. https://doi.org/10.14321/waterpathogens.46 Acknowledgements: K.R.L. Young, Project Design editor; Website Design: Agroknow (http://www.agroknow.com) Last published: August 1, 2018 Paragonimus spp. Summary mexicanus. In cerebral paragonimiasis, seizure, headache, visual disturbance, motor and sensory disturbances are the 5 major clinical symptoms. Human paragonimiasis is caused by nine species of the The most commonly performed diagnostic procedures for trematode genus Paragonimus, namely, P. westermani, P. paragonimiasis include sputum examinations for eggs and africanus, P. heterotremus, P. kellicotti, P. mexicanus, P. serologic tests to detect circulating antibodies or antigens siamensis, P. skrjabini, P. skrjabini miyazakii, and P. using ELISA or immunoblotting. uterobilateralis. The drug of choice is praziquantel at the dose of 25 mg/kg The geographical distribution of each species is as follows: three times daily for 2-3 days. In severe infections, a second P. westermani is distributed worldwide (including Oceania set of treatment may be needed. Triclabendazole can be and North America), but mostly in Asia, P. africanus in used in P. uterobilateralis, P. mexicanus, and P. skrjabini West Africa (Cameroon, Guinea, Nigeria, and Ivory Coast), infections, however, its efficacy on P. westermani infection, P. heterotremus in Asia (China, Vietnam, Thailand, Laos, in particular, cerebral infections, remains to be elucidated. and India), P. kellicoti in USA and Canada, P. mexicanus in To prevent paragonimiasis, eating undercooked freshwater Mexico and South America (Peru, Ecuador, Costa Rica, crab (including the pickled or drunken crab) and crayfish Panama, and Guatemala), P. siamensis in Thailand and Sri should be avoided. Avoidance of consuming undercooked Lanka, P. skrjabini in East Asia (China, Thailand, Japan, boar meat is also recommended in endemic areas. Sanitary treatment of wastewater which may contain the eggs of Vietnam, and India), P. skrjabini miyazakii in Japan, and P. Paragonimus spp. will help to block their life cycles. uterobilateralis in West Africa (Nigeria, Liberia, Guinea, Ivory Coast, and Gabon). To complete the life cycle of Paragonimus spp., three kinds 1.0 Epidemiology of the Disease and Pathogen of hosts, namely, the snail first intermediate host, the crustacean (crabs and crayfish) second intermediate host, Human paragonimiasis is caused by flukes of the and the mammalian definitive host are needed. Eggs trematode genus Paragonimus. They can infect the lungs as liberated from the definitive host contained in the sputum well as extrapulmonary sites, including the thorax, or feces enter the mountain water or sewage water and abdomen, skin, brain, spinal cord, and other miscellaneous infect the snails. Cercariae emerging from the snails infect organs and tissues. Taxonomically, more than 56 different crabs or crayfish to become metacercariae. When Paragonimus species have been described in the literature; mammalian animals eat the crabs or crayfish, the however, 16 to 17 species were found synonymous with metacercariae develop to adult flukes. other species and 36 species are considered to be valid Paragonimiasis is basically a pulmonary disease; however, (Blair et al., 1999; Narain et al., 2010; Chai, 2013a). Among it can also occur in extrapulmonary sites including the them, human infections are caused mainly by 9 species, brain and spinal cord. Clinical features of pulmonary which include P. westermani, P. africanus, P. heterotremus, paragonimiasis include bloody sputum, cough, chest pain, P. kellicotti, P. mexicanus, P. siamensis, P. skrjabini, P. night sweating, and lethargy, and frequently resemble skrjabini miyazakii, and P. uterobilateralis (Table 1) (Chai, those of pulmonary tuberculosis. Cerebral or spinal 2013a). Most of human paragonimiasis cases occur in Asia, involvements are most common in P. westermani, but can Africa, and North and South America (Narain et al., 2010; also occur in P. skrjabini, P. skrjabini miyazakii, and P. Chai, 2013a). Table 1. Paragonimus spp. reported from humans. Country of first Country of current distribution Species of Paragonimus Synonyms* report Cameroon, Guinea, Nigeria, Ivory Coast West Cameroon P. africanus Cameroon, Nigeria, Liberia, Guinea, Ivory Coast, Gabon Cameroon P. uterobilateralis P. hueitungensis, P. szechuanensis, P. China, Thailand, Japan, Vietnam, India China (Guangdong) P. skrjabini (skrjabini) veocularis China, Vietnam, Laos, Thailand China (Guangxi) P. heterotremus P. tuanshanensis P. assymetricus, P. India, China, Taiwan, Korea, Japan, edwardsi, P. filipinus, P. Southeast Siberia, Vietnam, Sri Lanka, macacae, P. India P. westermani Nepal, Pakistan, Papua New Guinea, philippinensis, P. USA pulmonalis, P. ringer Japan Japan P. skrjabini miyazakii P. miyazakii 3 Paragonimus spp. Country of first Country of current distribution Species of Paragonimus Synonyms* report Mexico, Peru, Ecuador, Costa Rica, P. ecuadoriensis, P. Mexico P. mexicanus Panama, Guatemala peruvianus Thailand, Sri Lanka, New Guinea Thailand P. siamensis USA, Canada USA (midwest) P. kellicotti The majority of the above information was obtained from Blair et al. (1999) and Chai (2013a); *The same (invalid) species as that of the left column. 1.1 Global Burden of Disease 1.1.1 Global distribution Figure 1. Worldwide distribution of paragonimiasis from WHO report in 2015 ( World Health Organization, 2015a) The global burden of paragonimiasis cases has been estimated to be about 20 million infected people globally (Toscano et al., 1994; Blair et al., 1999) and 293 million people at risk (Keiser and Utzinger, 2005; World Health Organization, 2015a) (Figure 1). However, these may be far underestimates (Chai, 2013a). In some areas, the prevalence shows a decreasing tendency, but in others new endemic foci are discovered or an increasing trend of infection is notified due to an increase in consumption of crabs (Chai, 2013a). The prevalence is in general higher in men than in women, and higher in young children than in adults (Walker and Zunt, 2005). 1.1.2 Morbidity, DALYs dyspnea (44%), myalgia (44%), and night sweats (44%) (CDC, 2010). In the chronic phase, pulmonary 1.1.2.1 Morbidity manifestations include cough, expectoration of discolored sputum, hemoptysis, and chest radiographic abnormalities; Paragonimiasis generally causes considerable degrees these symptoms could be confused with TB (CDC, 1999). In of morbidity and, in rare occasions, mortality. Only a few abdominal paragonimiasis, the worms may cause less cases whose worm burden is very low (with only 1-2 worms) definite symptoms, but intra-abdominal masses may be may undergo subclinically. The acute phase of palpable (Meyers and Neafie, 1976), and abdominal pain, paragonimiasis (pulmonary and extrapulmonary types) diarrhea, abdominal rigidity, and tenderness may be consists of various disease manifestations, such as presented (Choi, 1990). In urinary infections, urinary diarrhea, abdominal pain, fever, cough, urticaria, frequency and dysuria may occur (Choi, 1990). In cerebral hepatosplenomegaly, pulmonary abnormalities, and infections, seizure, headache, visual disturbance, motor and eosinophilia (CDC, 1999). In pulmonary infections, general sensory disturbances, optic atrophy, mental deterioration, acute symptoms include fever (100%), cough (100%), hemiplegia, hemi-hypalgesia, and homonymous weight loss (56%), malaise (56%), chest pain (44%), hemianopsia may occur (Oh, 1969). In spinal 4 Paragonimus spp. paragonimiasis, weakness of the legs, paravertebral Paragonimus spp. cause a foodborne burden of 1.0 million radicular pain, urinary difficulty, and sensory and motor DALYs (Havelaar et al., 2015). Table 2 shows the global disturbances in the lower extremities may occur (Oh, number of Paragonimus spp. infected patients through 3 1968b; Choi, 1990). parameters of years lost to disability (YLD = 1,033,097), years of life lost (YLL = 15,535), and disability-adjusted life 1.1.3.2 DALYs years (DALYs = 1,048,937). In 2005,